Bottom ring assembly



Oct. 16, 1962 w. w. URMETZ ETAI. 3,058,182

BOTTOM RING ASSEMBLY Filed oct. 14. 1960 s sheets-sheet 1 23 INVENTORSMIL r6@ M4 faMsrz By JOEL C .CARPENTER 14n-ORNE Ys OC- 16, 1962 w. w.URMETZ ETAL BOTTOM RING ASSEMBLY 5 sheets-sheet 2 Filed Oct. 14, 1960NTORS WAL re@ 1M @METZ By ha C. CARPENTER Q f. Afro NEYS v 0d 16, 1952w. W. URMETZ ETAL. 3,058,182

BOTTOM RING ASSEMBLY Filed Oct. 14. 1960 5 Sheets-Sheet 3 HIM X LINVENToRs WALTER Mnl/@Mrz f'/ S, BY JOEL C. CARPE/mm Arro EVS UnitedStates Patent Utilice 3,058,182 Patented Oct. 16, 1962 3,053,182 BSTOMRENS ASSEMBLY Walter W. Urinetz, Seven Hills, and loel C. Carpenter,

Chagrin Falls, Gino, assignors to Oglehay Norton Cornpany, Cleveland,Gliio, a corporation of Delaware Fiied Got. 14, 195o, Ser. No. 62,757it) Claims. (Cl. 22-147) This invention relates to a bottom ringassembly for a hot top used with an ingot mold in the pouring of moltenmetal, such as steel, to produce an ingot.

More particularly the invention relates to a refractory bottom ring andwiper strip combined therewith and constituting a unit assembly.

This application is a continuation-in-part of Urmetz and Carpenterapplication ySerial No. 815,852, now abandoned, filed May 26, 1959.

As is well known in the art, hot tops are placed in the open upper endsof ingot molds and the molten metal is poured through the hot tops intothe molds until they are filled and the hot tops contain a volume of themolten metal sufficient for the hot tops to function to feed the moltenmetal into the pipes or shrinkage cavities tending to form in thesolidifying ingots.

A common form of reusable -floating type hot top comprises a refractorylined metal casing to the lower end of which a single use refractorybottom ring is attached by means of wire attaching clips.

The hot top usually is provided with a sheet metal wiper strip, thefunction of which is to form a seal between the hot top and the innerwall of the ingot mold to stop off the rising molten metal that entersthe clearance space between the hot top and said wall. In other words,the function of the wiper strip is to seal off this clearance space toprevent the molten metal from rising too far therein or from overflowingthe top edge of the mold. When the molten metal rises too far in thisclearance space it is apt to form a fin around the hot top casing whichwould cause stickers when the hot top is being stripped from thesinkhead and the mold after the ingot has solidified. If the moltenmetal overilows the upper end of the mold and solidies it can producehanger ingots causing hanger cracks on the surface thereof andinterfering with the floating movement of the hot top relative to theingot mold.

Wiper strips have been used in sets of a plurality of separate strips toa hot top and which strips conjointly extend completely around the lowerend of the hot top casing. These wiper strips have an attaching portionthat extends between the upper face of the bottom ring and the lower endof the casing of the hot top and are held in position by the bottom ringwhen it is secured to the casing by the attaching clips. The wiperstrips have wiper lips which are integral with the attaching portionsand project angularly and laterally upwardly of the periphery of the hottop.

To obtain correct positioning of the wiper strips relative to the ringand hot top casing the wiper strips in some instances have been providedwith positioning tabs that iit into locating recesses formed in thebottom ring. Unless these positioning tabs and locating recesses arecorrectly interengaged the wiper strips may not be properly positionedso their wiper lips can have correct engagement with the mold wall. lnthose instances wherein the casings of the hot tops are old and somewhatworn or distorted the bottom rings may not seat correctly against thelower ends of the hot top casings and this could cause the wiper stripsto be improperly positioned so that their wiper lips lwill not makeeffective contact with the mold wall and provide the necessary sealbetween the hot top and the mold Wall.

The most generally used form of wiper strip is one secured in positionby its attaching portion extending between the upper face of the bottomring and the lower end of the hot top casing. Consequently the line ofcontact of the angularly and upwardly projecting wiper lip with the moldWall is above the plane of the upper face of the bottom ring. Thisresults in the molten metal having unrestricted freedom to `rise intothe clearance space between the hot top and the inner wall of the molduntil it contacts the wiper lip, and consequently increases thelikelihood of the formation of fins about the lower yend of the hot topwhich might cause stickers Also reliance against the molten metaloverflowing the mold depends on the functioning of the `wiper lip.

The most usual form of wiper strip does not protect the bottom ringagainst damage by engagement with the top of the mold when the hot topwith the ring assembled thereon is lowered into the mold and is notproperly aligned with the mold opening. This is particularly true whenthe hot top is inserted into a mold having a close fitting opening.Damage thus occurring to the refractory bottom ring may cause brokenpieces or chips thereof to fall into the ingot mold and this may resultin inclusions in the ingot unless such refractory pieces or chips areremoved before the pouring of the molten metal.

In preparing a hot top for use the metal casing is mounted in invertedposition on a preparation stand and the bottom ring is placed on the nowuppermost lower end of the casing. 'Ihen the separate wiper strips arepositioned by inserting the attaching portions thereof between thebottom ring and the lower end of the casing. Following this theconventional attaching clips are positioned and are connected to thevbottom ring and the casing to hold the bottom ring and wiper strips inposition relative to the casing. This preparation procedure is timeconsuming. Also the bottom rings and the separate wiper strips prior toapplication to the casings of the hot tops must be separately shipped,stored and handled.

Efforts have been made to iind satisfactory methods of securing thewiper strips to the bottom rings during .the manufacture of the bottomrings. These efforts have included attempts to mold the wiper stripsinto the rings during the molding of the latter and this requiredspecial molding equipment for forming the rings and adds considerably tothe cost of manufacture.

Efforts have been made to mechanically secure the wiper strips to thebottom rings and this would require that the rings be provided withcored holes, the formation of which complicates and slows down the ringmolding operation. The mechanical attachment of the Wiper strips to therings usually necessitates a costly operation such as riveting or theuse of other mechanical securing means.

As above stated, a number of separate conventional wiper strips must beused each time the wiper strips are assembled with the hot top and thebottom ring and usually at least four wiper strips are required. Thismeans that the separate wiper strip pieces must be handled separatelyfrom storage and each piece separately inserted and positioned betweenthe hot top casing and the bottom ring during the preparation of the hottop for each pouring operation.

According to the present invention a vbottom ring assembly iscontemplated that' includes a wiper strip means as part thereof andwhich eliminates the disadvantages of the conventional wiper strips andthe manner of their securement to the hot tops and rings. In addition,the invention contemplates a bottom ring assembly of this characterwherein the functioning of the wiper strip means to seal off the moltenmetal rising in the ingot mold is substantially increased in efficiencyand the likelihood of stickers or of hanger ingots is minimized. In thislatter connection the bottom ring assembly embodying the invention is soconstituted that as the hot top moves in the ingot mold and the wiperlip of the wiper strip means engages the wall of the mold and is ilexedby such engagement the attaching portion of the wiper strip means at itsjunction to the wiper lip as a fulcrum will have a rolling action on theperiphery of the bottom ring and will `cause the attaching portion at alocation spaced axially downwardly from the wiper lip to move into theclearance space between the hot top and the -wall ofthe mold and thussubstantially restrict this clearance space at a point closely adjacentto the lower entrance to such space. Therefore the molten metal isblocked or substantially blocked at the threshold of the clearance spacefrom rising therein in a substantial volume thus lessening theproduction of fins or the likelihood of overllowing the mold whereby thedanger of hot top stickers and hanger ingots is substantially reduced.This blocking of or reduction in the entrance to the clearance spacesupplements the sealing function of the wiper lip.

In the pouring of molten metal into ingot molds the pourer shouldmomentarily shut olf the flow of metal when molten metal in the moldbegins entering the clearance space between the hot top and the wall ofthe mold. This interruption is to allow the molten metal which hasentered the clearance space to solidify sufficiently to seal off suchspace.

One of the purposes of the wiper strip is to produce a chill in themolten metal which has entered the clearance space and contacted thewiper strip to thus facili- 'tate the required degree of sealingsolidi'cation of such molten metal.

In accordance with the present invention the chilling effect of theWiper strip means on the molten metal at or in the clearance space isincreased since both the wiper lip and the attaching portion of thewiper strip means which, due to the rolling action referred to has-rnoved into the clearance space, are effective for this purpose.

Also the present invention contemplates a wiper strip and bottom ringassembly which has manifold manufacturing and functioning advantagesover those previously used or proposed, many of which will later beexpressly pointed out.

According to the present invention assembly includes the use of anintegrated wiper strip means for thc entire periphery and a portion ofthe lower face of the bottom ring, as distinguished from the use of -aplurality of separate wiper strip pieces inserted separately between thelower end of the hot top casing and the upper face of the ring duringthe preparation of the hot top. This wiper strip means can be assembledreadily on and secured to the bottom ring in a simple assemblingoperation to constitute with the bottom ring a unitary assembly. Thiscan be done in the plant of the manufacturer of the bottom rings andwiper strips and then the bottom ring assemblies can be handled,shipped, stored and applied to the hot tops as units with the resultantadvantages incident thereto.

The assembly contemplated by the present invention provides a protectionto the refractory bottom rings against the breaking or chipping of theedges or corners thereof during shipment and storage and duringinsertion of the hot tops into the molds. The unitary assembly of thebottom rings and wiper strip means has the advantages of conning andstrengthening the bottom ring protectively by the embracing wiper stripmeans thereby eliminating the likelihood of reactory pieces or chips ofthe bottom rings falling into the molds when the ring and wiper stripassembly attached to the hot top is being lowered into the mold andunless the vchips are removed from the molds, they may cause seriousinclusions in the metal ingots.

the bottom ring v The bottom ring and wiper strip unitary assembly ofthe present invention assures the correct positioning of the wiper stripmeans since the strip means is an integrated one and is attached to andbacked up by the bottom ring and constitutes therewith a unitaryassembly and hence is not subject to being disturbed from its properposition during the insertion of the hot top into the mold.

The bottom ring assembly embodying the invention possessesmanufacturing, assembling and functional advantages in addition to thoseabove referred to and many of which will be mentioned during thedetailed description of embodiments of the invention which is to followand which embodiments are illustrated in the accompanying drawingsforming part of this specification and where- FIG. l is a sectional viewthrough a reusable composite hot top of the floating type, to the lowerend of the metal casing of which is attached a bottom ring assemblyembodying the present invention, the hot top being illustrated asinserted into the open upper end of an ingot mold which is fragmentarilyshown in section and prior to the wiper lip of the wiper strip meanshaving contacted said mold.

FIG. 2 is a fragmentary view of the lower right hand portion of FIG. lbut on a substantially enlarged scale as compared to FIG. l.

FIG. 3 is a view similar to iFIG. 2, but illustrates the relationship ofthe bottom ring assembly -with respect to the mold after the hot top hasmoved farther into the mold and the Wiper lip of the wiper strip meanshas engaged and been exed upwardly by the inner wall of the mold and theattaching portion of the wiper strip means, due to its rolling action onthe periphery of the bottom ring, has moved outwardly thereof toward theinner wall of the mold to block or substantially block the entrance -tothe clearance space bet-Ween the hot top and said inner Wall.

FIG. 4 is a plan view of the bottom ring assembly shown in `the previousviews but detached from the casing of the hot top.

FIG. S is an elevational view of the bottom ring and wiper stripassembly of FIG. 4 but with said ring and strip separated and prior tobeing combined into the unitary assembly.

FIG. 6 is a sectional view taken substantially on line 6--6 of FIG. 3looking in the direction of the arrows.

FIG. 7 is a fragmentary top plan view of va bottom ring and wiper stripassembly embodying the invention but in which the wiper strip meansdiiers specifically in structure from the wiper strip means shown in thefirst disclosed form of the invention.

FIG. 8 is a sectional view taken substantially on line 8 8 of FIG. 7looking in the direction of the arrows.

FIG. 9 is a fragmentary sectional view of the embodiment shown in FIG. 7and is similar to FIG. 3 but is taken in a slightly diierent verticalplane than is FIG. 3, namely, along line 9-9 of FIG. 7 looking in thedirection of the arrows.

FIG. 10 is a plan View of yone complete element of Vthe wiper stripmeans and -of a portion of :an adjacent and like element of the wiperstrip means of the embodiment of FIG. 7 and with said complete elementand ysaid adjacent element being illustrated in separated relationshipprior to being secured together.

FIG. ll is a side elevational view of the complete elcment of the wiperstrip means shown in FIG. 10.

FIG. 12 is a plan view of a bottom ring and wiper strip assembly of adifferent form than those previously shown but embodying the presentinvention and wherein the bottom ring is formed of two substantiallyU-shaped sections with the wiper strip means unitarily Iassembled witheach section and the sections constituting the two assemblies adapted tobe separately applied and secured to the casing of a large sizerectangular hot top, one section being shown in full lines and the othersection in dash lines.

FIG. 13 is a fragmentary broken away top plan view on a large scale ofthe embodiment shown in FIG. 12 and illustrates two of the adjacentelements of the wiper strip means `of the assembly separated from thebottom ring section and from each other prior to being interconnectedand united with the bottom ring U-shaped section.

FIG. 14 is a detail end elevational view of the wiper strip means shownin FIG, 13 and is taken looking at FIG. 13 substantially from line 14-14thereof.

FIG. l5 is a plan View showing `an embodiment of the invention when usedin connection with a round uted bottom ring formed of separate segmentsand with the wiper strip means of the combination integrated with eachsegment and having portions wrapped around the ends of the segmentssimilarly as in the form shown in FIG. 12, one segment being shown infull lines and the others in dash lines, and

FIG. 16 is a view similar to FIG. 12 but illustrates the invention asembodied in a bottom ring formed of separate quarter sections, one ofwhich is shown in full lines and the two 'adjacent sections in dashlines.

The hot top shown in FIG. 1 comprises the usual metal casing 16 which isillustrated as a two-part casing but it could be a one-part casing. Theinterior of the casing 16 is lined with refractory material which isillustrated in the form of irebrick 17 as lwill be understood in theart. A refractory bottom ring 18 is secured to the lower end of the hottop so as to underlie the hot top casing 16 and the brick lining 17 aswill be understood in the art.

The hot top in use is positioned in the upper end of an ingot mold 19and molten metal is poured into the mold to till the same and provide aquantity thereof in the hot top to form a sinkhead for a purpose wellknown in the art. The bottom ring 18 has Ian upper planar surfaceportion 18a which underlies the lower end of the casing 16 and an innerupstanding continuous rib portion 18h which extends upwardly within thelower end of the casing 16 and underlies the lower end of the refractorylining 17 as is well understood in the art. The bottom ring is securedto the hot top by means of substantially L-shaped wire attaching clips20 which have a portion located beneath the bottom ring and provided atits inner end with an opstanding -leg portion 20a having a hook at itsupper end which engages in a recess 18a` formed in the inner periphery`of the bottom ring as is well known in the art. The wire attachingclips 29 have a second upstanding leg portion 20h located outwardly -ofthe outer periphery of the bottom ring and casing land provided at itsupper end with a hook that engages in a bushing 21 carried by the casing16 all as is well known. The bottom ring 18 is secured to the casing 16by a number of the attaching clips 20, at least four such clips beingused depending on the size and shape of the hot top and spaced apartaround the ring `and hot top.

The casing 16 and bottom ring 18 lare so dimensioned as to be positionedin the mold 19 with clearance space existing between the outer side ofthe casing 16 and bottom ring 18 and the wall of the mold. The width ofthis clearance space Will vary since ingot molds, ydue to manufacturingtolerances and other causes, may vary in `size resulting in tight orloose fitting molds relative to the hot top.

When molten metal is poured into the ingot mold the rise of this moltenmetal into the clearance space between the hot top and the mold wall isvisually gauged as a rule by the pourer and an error could result inmolten metal coursing up through the space and overflowing across thetop of the mold.

In the pouring of the molten metal the pourer usually interrupts thepouring operation for a short time interval when he estimates that themolten metal is entering the clearance space. This is for the purpose ofallowing the molten metal Whichhas entered the clearance space tosolidify sufficiently to seal oif additional metal entering and risingin said space when the pouring operation is resumed.

As previously stated it has been customary to provide a seal in the formof wiper strips which have their attaching portions clamped in positionbetween the lower end of the casing 16 and the upper surface 18a of thebottom ring 18 and which strips have integral wiper lips that extendangularly outwardly and upwardly from the periphery of the ring ,andcontact the wall of the mold when the hot top is inserted therein andfunction to limit the upward ow of the molten metal in the clearancespace between the hot top and the mold wall.

Heretofore it has been usual to employ a plurality of separate wiperstrips, i.e., one for each of the four sides of a rectangular hot top,`and new strips must be positioned and used for each pouring operationand this means increased time in preparing the hot top and ring for eachpouring operation.

The wiper lip of the wiper strip is dimensioned so it will tightlycontact the inner Wall of the mold when the hot top is inserted in themold and will be flexed upwardly 'by such contact since the wiper stripis usually formed of flexible sheet metal.

The wiper lip of the wiper strip in addition to providing a mechanicalseal due to its contact with the mold wall also has a chilling effect onthe molten metal in the clearance space that contacts the wiper lip andthis facilitates the required solidication of such 4molten metal duringthe pause in the pouring operation.

The description heretofore set forth covers conventional matters. Thebottom ring assembly according to the present invention will now bedescribed. The Wiper strip means of the assembly may be a unitarystructure and extend completely around the periphery of the bottom ring.The wiper strip means may be made as an integral stamping or it may bemade of several stampings secured together to form the complete unit as,for instance, by weldin-g, riveting or otherwise suitably securing theseveral stampings together. The wiper strip means preferably is formedof sheet metal, although it could be formed of other suitable materials.

The wiper strip means of the embodiment shown in FIGS. l to 6 inclusivehas 'an attaching and bottom ring engaging portion formed of a flangepart 22 which extends beneath and contacts the lower face of the bottomring 18 but is capable of sliding movement thereon. The flange part 22is integral with and extends from the lower end of a verticallyextending part 23 which, when applied to the bottom ring, contactsclosely the outer periphery of the bottom ring as clearly indicated inFIG. 2.

The flange part 22 and vertical part 23 iit the lower outer edge of thering with a fairly close fit and can be telescoped thereon. At the upperend of the vertical part 23 of the attaching and bottom ring engagingportion of the wiper strip means there is an integral outwardly andupwardly inclined or fflared wiper lip 24. The wiper strip means isapplied to or telescoped on the bottom ring as a unit and is held inposition on the bottom ring by its t thereon and by the engagement ofupset knobs 25 formed in the vertical part 23 of the wiper strip meansin indentations or recesses 26 formed in the outer periphery of thebottom ring, or by other cooperating means intertting each other andlocated on the ring periphery and the vertical part Z3.

The wiper strip means could be heated before application to the ring andthen cooled to shrink into tight engagement with the ring, and in suchevent the mechanical interlitting means above referred to might beomitted.

The Wiper strip means and bottom ring 18 may be formed with anydesirable number of cooperating knobs 25 and depressions or recesses 26and for purposes of illustration two pairs of the cooperating knobs anddepressions have been shown for each side of the wiper strip means andbottom ring, although the number could be lesser or ygreater as requiredand they can be located in any desired position. The hot top, bottomring and wiper strip means have been illustrated as rectangular, but itwill be understood they might be circular, square or otherwise shaped.

The wiper strip means can be assembled on the bottom rings to constituteunits therewith by the manufacturer of the bottom rings and wiper stripmeans before shipment of the same to the ultimate user, that is thebottom rings with the strip means mounted thereon can be shipped ascomplete unit assemblies.

When the strip means are assembled on the bottom rings by themanufacturer prior to shipment and prior to use by the ultimate user,the 4wiper strip means serve to protect the lower outer edges of thebottom rings against chipping, cracking or other damage during shipment,storage and handling. Also it will be noted that the wiper strip means,due to tightly embracing the bottom rings, strengthen the latter inaddition to protecting the same and function to retain any crackedportions of the rings in proper position with respect to the rings.

It will be noted that when the bottom ring assembly of the presentinvention is secured to the lower end of the hot .topl the attachingclips 20 extend beneath the flange part 22 of the attaching portion ofthe wiper stripy means and upwardly alongside but outwardly of thevertical part 23 thereof and through cutouts or slots 27 formed in :thewiper lip 24.

Also the vertical -part 23 and the ange part 22 of the wiper strip meansat their `ang-le of interconnection are provided directly below theslots 27 with slots 2S, the

vertical portion of which extends a substantial distance upwardly of thevertical part 23 from the lower end thereof for a purpose later to beexplained.

In order to increase the flexibility of the wiper lip, particularly atthe corners thereof, said lip may be provided with slits 29, four ofwhich are indicated in FIG. 4, but it will be understood that the numberof slits 29 may be increased as is found desirable. Inasmuch as thewiper strip means is applied as a unit to the bottom ring, its correctpositioning on the bottom ring is assured and it provides protection forthe bottom ring including the outer lower edge and corners thereof.

Referring now to FIGS. 1 and 2 wherein the bottom -ring assembly isshown secured to the lower end of a hot top and the latter is startingits insertion movement linto the mold 19, it will be noted that thewiper lip 24 of the wiper strip means is of a length t overlie somewhatthe upper end of the mold. The vertical part 23 of the wiper strip meansacts to Ifacilitate, and guide the insertion of the hot top into themold and with the flange part 22 thereof protects the refractory ring.

Now assuming that the hot top has moved into the mold 19 from theposition shown in FIG. 2 to that shown in FIG. 3, it will be noted thatthe engagement of the wiper lip 24 `of the wiper strip means with themold has flexed said wiper lip upwardly and that its free end isengaging the inner wall of the mold to provide a seal. Although thewiper lip 24 ilexes at the junction between its inner end and the upperend of the vertical part 23 of the wiper strip means, this angularjunction has ia substantial measure of stiifness. Therefore the flexingof the vwiper lip 24 causes the angular junction between the lip .22 atthis time present a block or a substantial block to the entrance ofmolten metal into the clearance space between the hot top and the innerwall of themold. In the case of a loose mold the vertical part 23 of thewiper strip means may move closely adjacent to but without contact withthe inner Wall of the mold, while in the instance of a tight mold theremay be contact.

As previously stated, the slots 28 in the vertical part 23 and flangepart 22 of the wiper strip means and over which the attaching clips 20lie provide clearance for the outward movement of these parts, it beingrecalled that the portion of the slots 28 in the vertical part 23 is ofsubstantial vertical length while the portion of the slots in the ilangepart 22 is shorter and extends horizontally. Also the ilange part 22 ofthe wiper strip means has outward sliding movement on the bottom face ofthe bottom ring when the vertical part 23 moves outwardly as described.It will also be noted during this rolling action and the outwardmovement of the parts 23 and 22 that the knobs 25 in said part 23 canmove outwardly relative to the recesses or depressions 26 in the bottomring.

From the foregoing it will be seen that when the hot top is in'operative position in the ingot mold the parts 23 and 22 of the wiperstrip means block or substantially block entrance to lthe clearancespace between the hot top and the mold and hence restrict the flow ofmolten metal into such clearance space. However, the molten metal whichmay rind its way into the clearance space is of reduced volume and isadequately sealed against rising -too far in said space or overilowingthe upper end of the mold by the wiper lip 24 of the wiper str-ip means.

It will be noted that the wiper strip means provides dual sealing `orrestricting points against undesired rising of the molten metal in theclearance space between the hot top and mold `and spaced apartvertically of the hot top and thus efficiently protects against thedanger of hot top stickers o-r hanger ingots.

Furthermore, the Wiper strip means of the bottom ring assembly of thepresent invention in addition to providing a more eiiicient mechanicalseal itself, has the further advantage of facilitating the requireddegree of solidication of the molten metal adjacent to or in theclearance space between the hot top and the mold during the momentarypause 'in the pouring operation, since the parts 22 a-nd 23 of the wiperstrip mean-s engaging such molten metal in addition to any engagementthereof by the wiper lip 24 increases the chilling eect of the vviperstrip means on the molten metal.

It will be noted that should the hot top be misaligned with the moldopening during the lowering of the hot top into the mold, the wiperstrip means of the assembly protects the refractory bottom ring againstdamage through inadvertent contact with the mold. In addition, the wiperstrip means prevents chips, or broken pieces of fthe bottom ring fromfalling into the mold and unless removed `from the mold causinginclusions in the ingot.

Reference is now made to FIGS. 7 to 11 inclusive wherein is shown abottom ring assembly embodying the invention but differing somewhat instructure from the bottom ring assembly previously described.

The hot top illustrated fragmentarily in FlG. 9 may be of the sameconstruction as the hot top illustrated in FIGS. l to 3 inclusive andhence the portions of the hot top shown in FIG. 9 are identified Aby thesame reference numerals as are `the corresponding portions of the hottop of FIGS. 1 to 3 inclusive. Insofar as the refractory bottom ring ofthe bottom ring and wiper strip means assembly shown in FIGS. 7 to l1 isidentical with the previously described bottom ring the lsame referencenumerals used to identify lthe different portions of the bottom ring.

The wiper strip means of the bottom ring assembly of FIGS. 7 to l1inclusive comprises a plurality of separate identical elements which aresecured together to provide a unitary wiper strip means that is appliedand is secured as a unit to the bottom ring and surrounds the peripheryrtw 9 of the bottom ring and extends beneath the lower face thereof.

-Each of the separate elements of the wiper strip means now beingdescribed has an attaching and bottom ring engaging portion formed of avertical part which lies against the outer periphery of the bottom ringand an integral inwardly extending flanged part 31 which underlies andcontacts the lower face of the bottom ring. The vertical part 3@ of eachelement is provided `at its upper edge with an integral outwardly andupwardly inclined or flared wiper lip 32. The vertical part 30l of eachelement is provided at its opposite curved ends with extended curvedtabs 33 and 33a. When the elements of the wiper strip means areassembled together the tabs 33a of the elements will `overlie the tabs33 of adjacent elements.

The tabs 33a of each element are provided with one or more lbutton-'lilenipples 34 which contact the tabs 33 of the adjacent elements. Forpurposes of illustration the button-like nipples 34 on the tabs 33a areshown as two in number and as being located adjacent the upper end ofthe part 30 and as being vertically spaced apart. The illustratedarrangement is a desirable one for a purpose later to be explained butit will be understood that the button-like nipples may vary in numberand location from the illustrated showing thereof.

The elements of the wiper strip means are assembled together in asuitable jig or fixture so that the tabs 33a overlie the tabs 33 ofadjacent elements while the curved opposite ends 32a of the wiper lip 32of each element overlie in one instance and underlie in the otherinstance the curved opposite ends 32a of the wiper lip 32 of adjacentelements as clearly shown `in FIG. 7 and can have movement relative toeach other when the strip means tlexes. The opposite ends of the flangeparts 31 of the elements are beveled to intert with the en'ds of theflange parts 31 of adjacent elements. The overlapping tabs 33a and 33are then secured together preferably by electric welding at the locationof the nipples 34, although they could be secured together by othersuitable means as, for instance, by riveting. When the tabs 33a and 33are secured together as by electric welding as indicated in FIG. 8, thenipples 34 of the tabs 33a are fused into the metal of the overlyingtabs 33a and 33.

It will be seen that when the tabs 33 and 33a are secured together theseparate elements of the wiper strip means are then united into a singleunit which can be applied and secured as such to the bottom ring of thebottom ring assembly. If the bottom ring is of rectangular configurationfor use on the lower end of a rectangular hot top, then the securedtogether tabs 33 and 33a are located at the corners of the wiper stripmeans unit and of the bottom ring. The Wiper strip means unit willtightly t and surround the periphery of the bottom ring as in thepreviously described form and the ange parts 31 will underlie Vandcontact the lower face of the bottom ring but will be capable ofmovement thereon. When the wiper strip means is positioned on the bottomring then by means of a suitable upsetting operation the securedtogether tabs 33 and 33a are deformed or pressed inwardly to provideportions 35 that ex-tend into receases 36 formed in the periphery of thebottom ring and which recesses, if the bottom ring ds rectangular, willbe at the corners thereof or at some other suitable location.

The wiper lips 32 of the wiper strip means are provided with slots 37through which the portions 29h of the attaching clips 30 can extend.Also the vertical part 30 and the flange part 31 of the wiper stripmeans are provided at their junction with cutouts or slots 38 verticallyaligned with the slots 37 and similar in purpose to the slots or cutouts28 of the form of the invention described with reference to FIGS. lthrough 6 inclusive; it being noted that the portion of the slots 38 inthe vertical par-t 30 of the wiper strip means extend a substantia-ldistance upwardly of said part from the lower edge thereof and arelonger than the portions of the slots 3S that are in the flange parts31. In addition, the wiper lips 32 may be provided with slits 39 tofurther increase tne flexibility of the wiper lips. Although these slits39 are illustrated as being -two in number for each section and aslocated adjacent the curved opposite ends 32a Iof the wiper lip sectionsso as to position said slits 39 adjacent to the corners of the bottomring assembly, it will -be understood that additional slitscorresponding to the slits 39 'can be provided in the wiper lips 32 ifdesired and at other locations.

It was previously stated that the curved opposite ends 32a of the wiperlips of the sections have overlapping relationship land since thesecurved ends are not interlocked against relative movement, theflexibility of the wiper lips at the curved ends is not .restricted yandis relatively free, particularly in -view of the slits 39. Also sincethe loverlap-ping tabs 33 and 33a of the vertical parts 3l? of the wiperstrip means are secured together preferably adjacent to the upper edgeof said parts 30 the wiper strip unit at the corners thereof will havethe required measure of freedom or adaptability so that under therolling action later to be referred -to of the junction between saidvertical parts 30 and wiper lips 32, said parts 30 can move outwardlyinto the oleanance space -between the bottom .ring and the mold. Alsoduring such movement the flange parts 3l can move outw-ardly along thebottom face of the bottom ring as in the previously described form.

It will be understood that when a hot top with the bottom ring and wiperstrip assembly of the construction shown in FIGS. 7 through 1l securedto the lower end of its casing is inserted into a mold and the wiperlips 32 thereof contact the mold, said lips 32 will be llexed upwardlyand at the same time a rolling action against the periphery ofthe bottomring will yoccur on the fulcrum at the junction between the wiper lips32 and the upper edge of the vertical parts 3G and cause said verticalparts and also said flange parts 31 to move outwardly with respect tothe bottom ring to block or substantially block the entrance to theclearance space between the hot top and lthe mold for the same purpose:and with the same advantages as have been pointed out with reference tothe description of the embodiment of the invention shown in FIGS. 1through 6.

'In FIGS. l2, 13 and 14 a further embodiment of the invention isillustrated. In the case of large size hot tops as, for instance, largesize rectangular hot tops, it has been customary to have the bottomrings formed of separate section-s as, Ifor instance, two substantiallyU-sha-pe-d sections, which are secured to the lower end of the casing ofthe hot top and combined extend cornpletely around said lower end of thecasing. This type of arrangement is shown in FIG. l2 wherein one of thesubstantially U-shaped bottom ring sections is indicated at 40 in `fulllines `and the other substantially U-shaped section 40 is yfragmentarilyshown in dash lines.

Each bottom ring section 40 is provided with the raised rib 18b on itsupper side and with the att-aching clip recesses 18e as in thepreviously described bottom rings. The `outer periphery of the bottomring sections 46 is illustrated as provided with curves or waves.

Each bottom ring section 40 has assembled and in- Itegrated therewiththree sections of a wiper strip means, with the two sections of saidmeans that are on opposite sides of the bottom ring being identical inconstruction, while the end section of said wiper strip means differssomewhat in structure from the other two as will soon bcome apparent.

All of the sections of the wiper strip means have an attaching andbottom ring engaging portion comprising a flange part 41 which extendsbeneath and contacts the lower face of the bottom ring section :and avertical part 42 integral with the flange part and extending verticallyof the periphery of the bottom ring section as will be understood fromthe description of the previously described forms of con-struction. Theupper edge of the vertical part 42 has the integral outwardly flaredwiper lip 43 extending therefrom. The vertical par-t 42 and the wiperlip 43 are provided with waves or curves corresponding to the contour ofthe periphery of the bottom ring section.

In order to provide suicient flexability in the wiper lip 43,particularly in view of its wavy configuration, said lip is providedwith a plurality of spaced slits 44. Also the wiper llip 43 is providedwith cutouts 45 through which Ithe attaching clips (not shown in FIGS.12 and 13) can extend as will -be well understood.

In vertical alignment with the cutouts 45 the flange part 41 andvertical part 42 of the wiper strip means are provided with slots 46with .the longer portion of the slots 46 being in the vertical part 42las Was the case of the slots 28 and 38 in the previously describedforms. It will be understood that the purpose of the slots 46 is thesame as lthe previously referred to slots 28 and 38.

The section of the wiper strip means for the closed end of thesubstantially U-shaped bottom ring section 40 is provided at itsopposite ends fand on the vertical part 42 thereof with projecting tabs47. The vertical parts 42 of the side sections of the wiper strip means'are provided .at the ends of said sections which are adjacent yto theopposite ends of the end section of the wiper strip means withprojecting tabs 4S. When the Wiper strip means sections are assembledtogether the tabs 47 and 48 overlap and are secured together by suitablemeans as, for instance, one or more welds similarly to the tabs 33 .and33a of the embodiment shown in FIGS. 7 to 11 inclusive.

rFhe opposite curved ends 43a of the wiper lip 43 of the end section ofthe wiper strip means slidably overlap the adjacent curved ends 43b ofthe wiper lip 43 of the side sections of the wiper strip means. When theunited end and side sections of the wiper strip means are assembled withathe U-shaped bottom ring section 40 the flange parts 41 of the wiperstrip means sections underlie and contact the bottom face of the lbottomring section while the vertical parts 42 of the wiper strip sectionsfollow the contour of and contact the periphery of the 4bottom ringsection 4t). The overlapped and secured together tabs 47 and 48 overliethe end corners 49 of Athe bottom ring section 4t). The bottom rin-gsection 40 on opposite sides of the corners 49 thereof is provided withrecesses 50 and 4the vertical parts 42 of the side and end sections ofthe wiper strip means are crimped or deformed to have portions 50aextending into the recesses 50.

In order to secure the free ends of the side sections 1of the wiperstrip means to the free ends of the U-shaped bottom ring sections 40said side sections can be said to -be wrapped around the free ends ofthe bottom ring sections. The arrangement for doing this will now bedescribed.

The yfree ends of the bottom ring sections 46 .are provided in theirupper surfaces with recesses 51 that extend from Vthe periphery of thebottom ring transversely toward the rib 1gb thereof and which recesseshave a horizontal supporting or engaging sur-face. The free ends 'of thebottom ring sections also are provided iat the inner ends of therecesses 51 and communicating therewith with vertical recesses 52. l

The vertical parts 42 -a-t the free ends of the side sections of thewiper strip means are extended and turned at right angles to provideintegral portions 42a which bear against the vertical free end surfacesof the bottom ring section 40. The por-tions 42a on their upper edgehave integral horizontal tabs 42h which fit into the recesses 51 in thebottom ring section and bear on the horizontal `supporting surfacesthereof. The portions 42a at vtheir fre-e ends have integral verticaltabs 42a` whi-ch loosely extend into the vertical recesses 52 in the'free ends of the bottom lring'section but allow the parts 42 and 41 tomove when the part 42 is rocked. The portions 42a on their lower edgehave an integral flange 42d which extends horizontally beneath theflange part 41 of the wiper `strip means. The flange 42d is oiset Itointert the flange part 41, but beyond the offset the flange 42d contactsthe underside of the bottom ring section 40. The iiange 42d may tbesecured to the flange part 41 of the wiper strip means by spot Weldingthe same thereto as indicated in FIG. 13 or by any other suitablesecuring means.

It will be understood that each bottom ring section 40 has assembledtherewith a wiper strip means formed of the two side sections and theend section in a manner previously described. Also it Will be understoodthat the assembled bottom ring and Wiper strip section is secured by theattaching clips to the lower end of the hot top casing and the free endsof said assembled bottom ring and wiper strip section abut the free endsof an identical section that is similarly secured to the hot top to forma complete bottom ring and wiper strip assembly on the lower end of thehot top. This is indicated in FIG. 12 by the one bottom ring and wiperstrip assembly section shown in full lines and the other such sectionshown in dash lines.

It will further be understood that the bottom ring and wiper stripassembly of the form shown in FIGS. 12 through 14 and embodying theinvention when secured to a hot top cooperatively with another suchassembly and the hot top is inserted into an ingot mold, the wiper lips43 will engage the mold and a rolling action against the periphery ofthe bottom ring sections will occur to cause t-he vertical part 42 andthe iiange part 41 of the wiper strip means to move outwardly and blockor substantially block the entrance to the clearance space between thehot top and the mold just as in the previously described forms, it beingrecalled that the loose engagement of the tab 42e` in the verticalrecess 52 permits this movement.

Inasmuch as the wiper lips are provided with slits 44 and the cutouts45, the wiper lips will have flexibility, particularly if the slits 44are located so as to interrupt the continuity of the curves in the wiperlips. Also since the overlapping curved ends of the wiper lips of theside sections and those of the end section are free to have limitedrelative movement, the exibility of the wiper lines.

`In FIG. 15 the upper surface of the bottom ring segments is indicatedat 53 and each segment is provided with a substantially arcuate upwardlyextending rib 181; and has the recesses 18e for the hooks on the innerends of the attaching clips not shown. The wiper strip means that isassembled and integrated with each ybottom ring segment has an attachingand bottom ring engaging portion formed of a flange part 54 contactingthe under surface of the bottom ring segment and a vertical part 55 thatis convoluted to conform to and engages the periphery of the bottom ringsegment just as in the previously described forms.

The upper edge of the vertical part 55 of the wiper strip means isprovided with the integral flared 4wiper lip 56. The wiper lip 56 hasthe slots S7 for the attaching clips and said slots 57 are shown aslocated in the crest of the convolutions of the wiper lip 56. Also thecurves of the wiper lip 56 are interrupted by one or more slits 58 whichwith the slots S7 provide the requisite exibility for the Wiper lip.

The opposite ends of the wiper strip means for each segmental bottomring section are wrapped around and are secured to the opposite ends ofsaid bottom ring segment in the same manner as are the free ends of thewiper strip means with respect to the free ends of the bottom ringsections in the form shown in FIGS. 12 through 14.

Each bottom ring segment 53 on its periphery is provided with a suitablylocated recess or recesses 59 and the vertical part 55 of the wiperstrip means is crimped or upset into said recesses 59 as indicated at60. It will be understood that the bottom ring segments each haveassembled therewith the wiper strip means and these assemblies areseparately attached to the lower end of the hot top casing so as toextend completely therearound with the ends of each assembly abuttingthe ends of adjacent assemblies. It will also be understood that theflange part 54 and vertical part 55 of the wiper strip means areprovided with L-shaped slots 61 similar to the previously describedslots 28, 3S and 46 and for the same purpose.

It will further be understood that when a hot top having secured theretothe circular bottom ring shown in FIG. 15 is inserted into a mold andthe wiper lip 56 is eXed by its engagement with the mold wall, therolling action of the junction between the wiper lip 56 and the verticalpart 55 takes place against the periphery of the refractory bottom ringand causes said vertical part 55 and flange part 54 to move outwardlytoward the wall of the mold to block or substantially block the entranceto the clearance space between the hot top and the mold.

In FIG. 16 a further embodiment of the invention is illustrated. Herethere is shown a portion of a large size rectangular bottom ring made upof quarter sections, one of which is shown in full lines while the twoadjacent ones are fragmentarily indicated in dash lines. Each bottomring section is substantially L-shaped and the upper surface thereof isindicated at 62. Each bottom ring section has the raised rib 18h and therecesses 18C for the attaching clips as in the previously describedforms.

Each bottom ring quarter section has assembled thereon a quarter orsubstantially L-shaped wiper strip means section. Each wiper strip meanssection has an attaching and bottom ring engaging portion including aange part 63 that contacts the underface of the bottom ring section anda vertical part 64 that engages the periphery of the bottom ringsection. The vertical part 64 has integral with its upper edge the aredwiper lip 65. This wiper lip 65 is sloted as at 66 for the attachingclips and has a number of spaced slits 67 therein to provide eXibilityfor the wiper lip, one of said slits being at the corner of the wiperstrip means section as illustrated in FIG. 16.

The opposite ends of each wiper strip means section are wrapped aroundand secured to the opposite ends of each bottom ring quarter section inthe same manner as are the ends of the wiper strip means sections in theforms shown in FIGS. 12 through 15. Each bottom ring quarter section ineach arm or leg thereof is provided on its periphery with one or morerecesses 68 into which the vertical part 64 of the wiper strip means iscrimped or upset as indicated at 69.

The embodiment of the invention shown in FIG. 16 functions in the sameway and with the same advantages as do the previously describedembodiments.

Although a number of different embodiments of the invention have beenillustrated and described herein, it will be understood that theinvention is susceptible of various modications and adaptations withinthe Scope of the appended claims.

Having described our invention we claim:

1. A bottom ring and wiper strip unit assembly for a floating compositetype hot top for an ingot mold and comprising a refractory bottom ringadapted to be secured to the hot top metal casing by attaching clips,and sheet material wiper strip means mounted on and united with saidbottom ring as a unit assembly therewith and including an attachingportion having a horizontal flange slidably contacting the lower face ofthe bottom ring and a vertical part integral with said llange andtiltably engaging the outer periphery of the bottom ring and from theupper edge of which extends angularly outwardly and upwardly an integralwiper lip adapted to be ilexed upyWardly by engagement with the moldwall, said flange vand said vertical part being provided Withinterconnecting openings located to be in the vertical plane thatincludes the attaching clips which secure the unit assembly to the hottop casing, whereby when the unit assembly is attached to a hot top andthe latter is inserted in an ingot mold and the wiper lip is flexedupwardly said vertical part tilts on the ring periphery at the junctionof said wiper lip and said part to cause said ange to slide on the lowerface of said ring into the clearance space between the hot top and themold wall at a location spaced inwardly of the mold from wiper lipengagement with said wall.

Z. A bottom ring and wiper strip unit assembly for a lloating compositehot top for an ingot mold as dened in claim l and wherein Said wiper lipis provided with attaching clip slots and the said openings in thevertical part of said Wiper strip means are elongated upwardly towardsaid wiper lip whereby when the unit assembly is attached to a hot topand the latter is inserted in an ingot mold and the wiper lip is flexedupwardly said vertical part tilts through a substantial angle on thering periphery at the junction of said wiper lip and said partnotwithstanding the presence of attaching clips to cause said ange toslide on the lower face of said ring a substantial distance into theclearance space between the hot top and the mold wall at a locationspaced inwardly of the mold from wiper lip engagement with said wall.

3. A bottom ring and wiper strip unit `assembly for a lloating compositetype hot top for an ingot mold and comprising a refractory bottom ringadapted to be secured to the hot top metal casing `by attaching clips,and sheet material wiper strip means mounted on and united with saidbottom ring as a unit assembly therewith and formed of a plurality ofseparate sections conjointly embracing the periphery of the ring, eachsection including an attaching portion having a horizontal flangeslidably contacting the lower face of the bottom ring and a verticalpart integral with said flange and tiltably engaging the outer peripheryof the bottom ring and from the upper edge of which extends angularlyoutwardly and upwardly an integral wiper lip adapted to be llexedupwardly by engagement with the mold wall, said llange and said verticalpart of each section being provided with interconnecting openingslocated to be in the vertical plane that includes the attaching clipswhich secure the unit assembly to the hot top casing, whereby when theunit assembly is attached to a hot top and the latter is inserted in aningot mold and the wiper lips of the sections are flexed upwardly saidvertical parts tilt on the ring periphery at the junction of said wiperlips and said parts to cause said anges to slide on the lower face ofsaid ring into the clearance space between the hot top and the mold wallat a location spaced inwardly of the mold froml wiper lip engagementwith said wall.

4. A bottom ring and wiper strip unit assembly for a floating compositetype hot top for an ingot mold and comprising a refractory bottom ringadapted to -be secured to the hot top metal casing by attaching clips,and sheet material wiper strip means mounted on and united with saidbottom ring as a unit assembly therewith and including an attachingportion having a horizontal flange slidably contacting the lower face ofthe bottom ring and a vertical part integral with said ange and tiltablyengaging the outer periphery of the bottom ring and from the upper edgeof which extends angularly outwardly and upwardly an integral wiper lipadapted to be flexed upwardly by engagement with the mold wall wherebywhen the unit assembly is attached to a hot top and the latter isinserted in an ingot mold and the wiper lip is llexed upwardly saidvertical part tilts on the ring periphery at the junction of said wiperlip and said part to cause said -ilange to slide on the lower face ofsaid ring into the clearance space between the hot top and the mold wallat a location spaced inwardly of the mold from wiper lip engagement withsaid wall.

5. A bottom ring and wiper strip unit assembly for a oating compositetype hot top for an ingot mold and comprising a refractory bottom ringadapted to be secured to the hot top metal casing by attaching clips,and sheet material wiper strip means mounted on and united with saidAbottom ring as a unit assembly therewith including an attaching portionhaving a horizontal flange slidably contacting the lower face of thebottom ring and a vertical part integral with said ange and tiltablyengag- Iing the outer periphery of the bottom ring and from the upperedge of which extends angularly outwardly and upwardly an integral wiperlip adapted to be iiexed upwardly by engagement with the mold wall, saidring being provided on its periphery with recesses and said verticalpart 'being provided with projections movably extending into saidrecesses, said ange and said vertical part being provided withinterconnecting openings located to be in the vertical plane thatincludes the attaching clips which secure the unit assembly to the hottop casing, whereby when the unit assembly is attached to a hot top andthe latter is inserted in an ingot mold and the wiper lip is ilexedupwardly said Vertical part tilts on the ring periphery at the junctionof said wiper lip and said part to cause said flange to slide on thelower face of said ring into the clearance space between the hot top andthe mold wall at a location spaced inwardly of the mold from wiper lipengagement with said wall.

6. A bottom ring and wiper strip unit assembly for a floating compositetype hot top for an ingot mold as defined in claim 5 and wherein saidsheet material wiper strip means is an integral stamping intertting andextending around the outer periphery of the ring and engaging the lowerface of said ring.

7. A rbottom ring and wiper strip unit assembly for a floating compositetype hot top for 'an ingot mold as de- Vstrip means are elongatedupwardly toward said wiper lip, Vwhereby when the unit assembly isattached to a Vhot top and the latter is inserted in an ingot mold andthe wiper lip is llexed upwardly said vertical part tilts through asubstantial angle on the ring periphery at the junction of said wiperlip and said part and due to the lever length of said part causes saidflange to slide on the lower face of said ring a substantial distanceinto the clearance space between the hot top and the mold wall at alocation spaced inwardly of the mold from wiper lip engagement with saidwall. Y

8. A bottom ring and wiper strip unit assembly for a floating compositetype hot top for an ingot mold as delined in claim 5 and wherein saidsheet material wiper strip means is formed of a plurality of separatesections conjointly embracing the pheriphery of the ring, each sectionincluding said horizontal ilange, said vertical part and Said Wiper lip;the vertical parts of said sections having end portions arranged inoverlapping relationship and secured to similar end portions of thevertical parts of adjacent sections, the projections of said Verticalparts which extend into the said recesses in the periphery of the ringbeing formed in the overlapping end portions of said parts.

9. A bottom ring and wiper strip unit assembly for a iloating compositetype hot top for an ingot mold as dened in claim 8 wherein said wiperlips are provided with attaching clip slots and said vertical partsextend upwardly to close proximity to the upper face of the ring and theopenings in said vertical parts are elongated upwardly from theinterconnecting openings in said flanges toward said wiper lips, wherebywhen the unit assembly is attached to a hot top and the latter isinserted in an ingot mold and the wiper lips are flexed upwardly saidvertical parts tilt through a substantial angle on the ring periphery atthe junction of said wiper lips and said parts and due to the leverlength of said parts cause said lianges to slide on the lower face ofsaid ring a substantial distance into the clearance space between thehot top and the mold wall at a location spaced inwardly of the mold fromwiper lip engagement with said wall.

l0. A bottom ring and wiper strip unit assembly for a oating compositetype hot top for an ingot mold and comprising a refractory bottom ringadapted to be secured to the hot top metal casing by attaching clips,said bottom ring being formed of a plurality of separate sections shapedto conjointly intert the lower end ofthe hot top, and sheet materialwiper strip means mounted on each ring section as a unit assemblytherewith and including an attaching portion having a horizontal angeslidably contacting the lower face of the ring section and a verticalpart integral with said ilange and tiltably engaging the outer peripheryof the ring section and from the upper edge of which extends angularly,outwardly and upwardly an integral wiper lip adapted to be flexedupwardly by engagement with the mold wall and provided with attachingclip slots, each of said ring sections and said Vertical parts of thewiper strip means having interengaging but relatively movable portionsmaintaining the wiper strip means assembled on the ring sections to beattached as a unit therewith to the hot top but with said vertical partstree to have tilting movement on the ring sections about the fulcrum atthe junction between the upper edge of said Yvertical parts and thewiper lips, said ilanges and said vertical parts being provided withinterconnecting openings in the vertical plane that includes said slotswhereby when the assembly is attached to a hot top and the latter isinserted in an ingot mold and the wiper lips are flexed upwardly saidvertical parts tilt on the ring periphery to cause said anges to slideon the lower faces of said ring sections into the clearance spacebetween the hot top and the mold wall at a location spaced inwardly ofthe mold from the wiper lip engagement with said wall.

References Cited in the tile of this patent UNITED STATES PATENTS2,258,483 Charman Oct. 7, 1941 2,300,077 Urmetz Oct. 2.7, 1942 2,426.748Rees et al. v .r Sept. 2, 1947

